Dropped frames never requested a keyframe, SessionEnded skipped ordered
stop (portal/TV/FFI leak, next start could abort), and a late end could
kill the following cast. Failed starts left PlatformClientPosix alive.
DLNA leaked its HTTP server and ignored portal EOS.
Also: start no longer blocks the daemon actor, IPC accept/request loops
stay up, HLS Range is clamped, LAN IP follows the renderer subnet, and
the picker closes before the portal dialog and handles Escape.
